We have play-time, which she thoroughly enjoys, every day. Her favorite toy is the wand that has pom-poms and feathers attached. Yes, I imagine if she was an out-door cat she would quickly become a hunter of birds. But she is happy to be an in-door cat so it is up to us to help her to slim down with extra play.
Having a scheduled play-time is a wonderful way to bond with your cat. They love nothing better than to have you all to themselves.